The present disclosure relates to support devices, such as mattresses, having pneumatic control devices, such as air supply/discharge valves that are used to supply air or empty compartments inflated with air, and having a plurality of compartments to be inflated with fluid such as compressed air.
In some prior art mattresses, these compartments are in the form of cylinders, each cylinder extending transversally relative to the longitudinal direction of the mattress and the different cylinders being placed side by side in the longitudinal direction of the mattress. Each compartment of some prior art mattresses has a fluid supply orifice and a fluid discharge orifice.
To fill/inflate a compartment, a first valve, typically an electrovalve controlling the supply via said supply orifice, is opened, then air is injected under pressure, then this first electrovalve is closed when the necessary pressure is reached while a second electrovalve controlling the discharge of fluid from said discharge orifice is kept closed. And, inversely, for emptying or deflating a compartment, for adjusting the pressure inside the compartment, said first electrovalve controlling the supply orifice is kept closed and the second electrovalve controlling the discharge from the discharge orifice is opened.
Mattresses of this type are used in medical environments as they ensure better distribution of the fluid inside the mattress. And, as a function of the number of electrovalves employed, they individually control the pressure and therefore the filling of the compartments in different zones of the mattress.